1. Field of the Invention
This invention relates to single-skin insulated roof or wall structures, and more particularly to improvements in a two-piece concealed-type attachment clip for securing panels to the structural elements of a building framework.
2. Description of the Prior Art
Single-skin roof or wall structures are known wherein lengths of blanket-type or roll-type insulation, arranged in side-by-side relation, span across plural structural elements. Concealed attachment clips overlying and fully compressing the insulation therebeneath, are secured to the subjacent structural elements. Panel members assembled in side-by-side interlocked relation, are secured to the structural elements by the concealed attachment clips. The full compression of the insulation at each clip site reduces the thermal efficiency of the structure. See for example U.S. Pat. No. 4,139,974 (FOX).
Substantially incompressible thermal spacers have been provided along the structural elements between adjacent clips. The thermal spacer provides support for the subsequently installed panels and adds to the thermal efficiency of the structure. See for example U.S. Pat. No. 4,213,282 (HECKELSBERG) and the RIBLOCK system illustrated and described on Page 92 of "Metal Building Review", Volume 16, No. 5, May, 1980. The thermal spacers constitute additional elements to be installed thereby increasing the materials cost, the erection time, and consequently the overall cost of the roof or wall structure.